The Biology of Chronic Lymphocytic Leukemia: Diagnostic and Prognostic Implications

Tuning the B-CLL microenvironment: evidence for BAG3 protein- mediated regulation of stromal fibroblasts activity

The Bcl2-associated athanogene-3 (BAG3) protein, a critical regulator of cellular survival, has been identified as a potential therapeutic target in various malignancies. This study investigates the role of BAG3 within stromal fibroblasts and its interaction with B-cell chronic lymphocytic leukemia (B-CLL) cells. Previous research demonstrated that BAG3 maintains the active state of pancreatic stellate cells (PSCs) and aids pancreatic ductal adenocarcinoma (PDAC) spread via cytokine release. To explore BAG3's role in bone marrow-derived stromal fibroblasts, BAG3 was silenced in HS-5 cells using siRNA. In co-culture experiments with PBMCs from B-CLL patients, BAG3 silencing in HS-5 cells increased apoptosis and decreased phosphorylation of BTK, AKT, and ERK in B-CLL cells, thus disrupting their pro-survival key signaling pathways. The observation of fibroblast-activated protein (FAP) positive cells in infiltrated bone marrow specimens co-expressing BAG3 further support the involvement of the protein in fibroblast-mediated tumor survival. Additionally, BAG3 appears to support B-CLL survival by modulating cytokine networks, including IL-10 and CXCL12, which are essential for leukemic cell survival and proliferation. A robust correlation between BAG3 expression and the levels of CXCL12 and IL-10 was observed in both co-cultures and patient specimens. These findings point out the need for a more in-depth comprehension of the intricate network of interactions within the tumor microenvironment and provide valuable insights for the selection of new potential therapeutic targets in the medical treatment of CLL.

Knowledge, skills, and confidence gaps impacting treatment decision making in relapsed/refractory chronic lymphocytic leukemia and mantle cell lymphoma: a quantitative survey study in France, Germany, and the United States

BACKGROUND

With recent advancements in the treatment of chronic lymphocytic leukemia (CLL) and mantle cell lymphoma (MCL), healthcare specialists may face challenges making treatment and management decisions based on latest evidence for the optimal care of patients with these conditions. This study aimed to identify specific knowledge, skills, and confidence gaps impacting the treatment of CLL and MCL, to inform future educational activities.

METHODS

Hematologists and hemato-oncologists (HCPs, n = 224) from France (academic settings), Germany, and the United States (academic and community settings) responded to a 15-minute quantitative needs assessment survey that measured perceived knowledge, skills, and confidence levels regarding different aspects of treatment and management of CLL and MCL patients, as well as clinical case questions. Descriptive statistics (cross tabulations) and Chi-square tests were conducted.

RESULTS

Four areas of educational need were identified: (1) sub-optimal knowledge of treatment guidelines; (2) sub-optimal knowledge of molecular testing to inform CLL/MCL treatment decisions; (3) sub-optimal skills when making treatment decisions according to patient profile (co-morbidities, molecular testing results); and (4) challenges balancing the risk of toxicities with benefits of treatment. Over one-third of the respondents reported skill gaps when selecting suitable treatment options and prescribing therapies and reported a lack in confidence to initiate and manage treatment. Larger gaps in knowledge of guidelines and skills in patient assessment were identified in MCL, compared to CLL.

CONCLUSIONS

This study suggests the need for continuing medical education specifically to improve knowledge of treatment guidelines, and to assist clinicians in developing skills and confidence when faced with clinical decision-making scenarios of patients with specific comorbidities and/or molecular test results, for example, through case-based learning activities.

Safety and Efficacy of Bendamustine and Rituximab (BR) Regimen in Indian Chronic Lymphocytic Leukaemia Patients

We investigated the safety and efficacy of bendamustine-rituximab (BR) in previously untreated symptomatic and advanced CLL patients, as there is no data available on BR from the Indian subcontinent.This retrospective study included 120 consecutive treatment naïve patients with CLL without del (17p), who were registered at the Department of Medical Oncology, AIIMS between January 2010 and July 2018. Bendamustine was given at a dose of 90 mg/m2 on days 1 and 2, combined with rituximab 375 mg/m2 rituximab on day 1, every 28 days for up to 6 courses. Event-free survival (EFS) was defined as the date of treatment to date of relapse, disease progression, or death due to any cause.The median age was 57 years (range: 30-75 years). As per the clinical Rai stage, 30 (25%) patients were in stage II, 42 (35%) were in stage III and 48 (40%) were in stage IV. ZAP70 was positive (> 20%) in 50%, CD 38 was positive (> 30%) in 33%, and CD49d was positive (> 30%) in 49% of cases. Beta-2 microglobulin (B2M) was elevated (≥ 3.5 mg/L) in 80% of cases. Fifty-five cases (50%, n = 110) were IGHV mutated. The mean number of cycles was 5 (1-6). The overall response rate (ORR) seen with BR was 90% and complete response was 45%. Median progression-free survival was 24 months with a median follow-up period of 29 months. Haemoglobin (< 10 g/dL), elevated B2 M, unmutated IGHV had a statistically significant adverse impact on EFS on univariate analysis but on multivariate analysis, only IGHV mutation status was found to had significance on EFS. The median EFS was 27 months in IGHV mutated versus 18 months in IGHV unmutated-CLL patients (p = 0.001). Grade 3/4 neutropenia, thrombocytopenia, anemia, and infections were observed in 30.6%, 8%, and 12% respectively. The most common non-hematological toxicity was skin rash which was grade 1/2 in 24 (20%) cases and grade 3/4 in 12 (10%) cases. This is the largest study from India to demonstrate the safety and efficacy of BR in symptomatic CLL patients. BR is an effective and safe regimen in the first-line treatment of CLL. Unmutated-CLL patients have inferior EFS than mutated-CLL patients. Skin toxicity was the most common adverse effect seen in our population which was observed in around one-third of cases.

Implementation of International Prognostic Index with flow cytometry immunophenotyping for better risk stratification of chronic lymphocytic leukemia

BACKGROUND

Current chronic lymphocytic leukemia (CLL) International Prognostic Index (IPI) stratifies patients based on clinical, molecular, and biochemical features; however, B-cell markers also influence CLL outcomes. Here, prognostic roles of CD11c, CD38, and CD49d were first evaluated, and then an immunophenotypic score was combined with CLL-IPI for risk stratification of CLL patients.

METHODS

A total of 171 CLL subjects were included, and surface marker expression was assessed by flow cytometry. Levels ≥30% were chosen as cut-off of positivity to a marker; then values of 1 (for CD11c and CD38) or 3 (for CD49d) were assigned and scores determined for each patient's clone immunophenotype.

RESULTS

CD49d positivity was significantly associated with simultaneous expression of CD11c and/or CD38, unmutated IGHV status, and higher β2-microglobulin levels compared to those with CD49d negativity. Moreover, CD49d⁺ patients experienced a shorter progression-free survival and time to treatment. When the immunophenotypic score was combined with CLL-IPI, patients with high-risk immunophenotype had a significantly lower time-to-treatment regardless CLL-IPI.

CONCLUSIONS

Our results suggested clinical utility of an integrated prognostic score for better risk stratification of CLL patients. These results require further validation in prospective larger studies.

The mitochondrial anti-apoptotic dependencies of hematologic malignancies: from disease biology to advances in precision medicine

Mitochondria are critical organelles in the regulation of intrinsic apoptosis. As a general feature of blood cancers, different antiapoptotic members of the BCL-2 protein family localize at the outer mitochondrial membrane to sequester variable amounts of proapoptotic activators, and hence protect cancer cells from death induction. However, the impact of distinct anti-apoptotic members on apoptosis prevention, a concept termed anti-apoptotic dependence, differs remarkably across disease entities. Over the last two decades, several genetic and functional methodologies have been established to uncover the anti-apoptotic dependencies of the majority of blood cancers, inspiring the development of a new class of small molecules called BH3 mimetics. In this review, we highlight the rationale of targeting mitochondrial apoptosis in hematology, and provide a comprehensive map of the anti-apoptotic dependencies that are currently guiding novel therapeutic strategies. Cell-extrinsic and -intrinsic mechanisms conferring resistance to BH3 mimetics are also examined, with insights on potential strategies to overcome them. Finally, we discuss how the field of mitochondrial apoptosis might be complemented with other dimensions of precision medicine for more successful treatment of 'highly complex' hematologic malignancies.